Mainframes process trillions of transactions annually in banking, insurance, and government, yet remain invisible to modern observability tooling. With OpenTelemetry's graduation and dedicated mainframe working group, that's changing.
This talk demonstrates how we've mapped z/OS subsystems (CICS, IMS, Db2) to OpenTelemetry semantic conventions, preserving mainframe-specific context like LPAR, virtualization and region.
We'll show live examples of distributed traces spanning from Kubernetes microservices through API gateways into COBOL transactions, and how structured logs integrate with cloud-native platforms.
Attendees will learn the technical challenges of instrumenting legacy systems, our approach to backward-compatible schema design, and how this work enables hybrid cloud architectures where mainframes remain first-class citizens.